The invention relates to a magnetic valve controlled injector for a storage (common rail) fuel injection system of a multi-cylinder internal combustion engine, comprising a multipart injector with an injector housing including a nozzle needle biased to a closed position by a spring disposed in a spring chamber behind the nozzle needle, a control piston disposed in a housing part and exposed to the fuel supply pressure and a valve element for controlling the fuel supply to the nozzle needle. The injector further includes at the side of the control piston remote from the nozzle needle a control chamber which is in communication with the pressurized fuel supply line by way of a passage extending through the control piston and including a valve element, and with a fuel drain line for releasing fuel by way of a magnetically controlled valve.
Such an injector is known for example from DE 196 12 738 A1. The injector disclosed therein includes a control piston with an integrated valve element. The control piston is guided in an upper and a lower housing part of the injector. The valve element is a cone-shaped rim extending around the control piston and forming a conical seating surface cooperating with a valve seat formed in the lower housing part. Because of the particular valve arrangement, the fuel supply line extends partially through the lower and partially through the upper housing part.
It is the object of the present invention to provide such an injector in which, with simple measures, internal sealing is improved while a slim injector design is maintained.